JP2011239436A - Video camera apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder capable of improving the quality of an image recorded in MPEG4 when simultaneously recording in MPEG2 and MPEG4 formats.SOLUTION: In an image encoder that outputs simultaneously input images as encoded streams by a first encoder and a second encoder having lower rate than the first encoder, a quantization coefficient, a quantization value, a generated code amount, and code information such as determination result of an intra-image and an inter-image of the first encoder are recorded, and the second encoder performs encoding using the recorded code information of the first encoder.

Description

  The present invention relates to a video camera apparatus.

  For example, MPEG2_Video (ISO / IEC13818-2) is a moving image compression method aiming at high rate and high resolution. Further, as a moving image compression method for the purpose of low rate and low resolution, there is, for example, MPEG4_Video (ISO / IEC 14496-2).

  Here, a method of performing MPEG4 rate control using side information (total code amount, etc.) when decoding MPEG2 when transcoding an MPEG2 stream into an MPEG4 stream has been proposed (Patent Document 1).

  On the other hand, a method of using a low-resolution video signal has been proposed for encoding a frame of a high-resolution video signal (Patent Document 2).

JP 2000-31363 A JP-A-11-136683

  The transcode disclosed in Patent Document 1 has one output and cannot simultaneously output and record high resolution / high rate image information and low resolution / low rate image information.

  The means for encoding the high-resolution image information by more effectively using the low-resolution video signal disclosed in the above-mentioned Patent Document 2 can improve the image quality of the low-resolution / low-rate image information. Can not.

  An object of the present invention is to provide an encoding apparatus capable of outputting image information with high image quality, a video camera apparatus using the same, and an encoding method.

  The object is achieved by the invention described in the claims.

  According to the present invention, image information can be output with high image quality.

Simple block diagram of MPEG2 / 4 simultaneous recording Block diagram of MPEG2 / 4 simultaneous recording MPEG2 / 4 simultaneous recording timing diagram Block diagram of video camera device Block diagram of digital signal input / output device

  Hereinafter, the present embodiment will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of an encoding apparatus according to the present invention. When an input image at the same time is encoded by the first encoding device 1 and the second encoding device 2, information on the generated code amount of the first encoding device, information on the quantization value, The second encoding apparatus performs encoding using the determination result between (Intra) and inter-image (Inter).

  FIG. 2 is a block diagram showing an embodiment of an encoding apparatus according to the present invention. In MPEG2 recording, an analog signal input from the camera unit 10 is converted into a digital image format by the image input unit and stored in the recording RAM unit 90. The MC unit (motion compensation unit) 30 reads an image necessary for performing motion compensation for each coding unit, and performs motion compensation. The Judge unit (Intra / Inter determination unit) 80 performs switching determination of Intra / Inter encoding, the DCT unit (discrete cosine transform unit) 40 performs DCT transformation, and the Q unit (quantization unit) 50 performs quantization. The rate unit (information amount control unit) 70 performs information amount control, and the VLC unit (variable length encoding unit) 60 performs conversion to an MPEG2 codeword to generate an MPEG2 stream. In addition, the decoded image locally decoded by the Q unit, the DCT unit, and the MC unit is stored in the recording RAM unit and used for motion compensation of the next frame.

  In MPEG4 recording, the moving image data digitized by the image input unit is scaled to the MPEG4 target image size by the Scaler unit (image resolution converting unit) 100 and stored in the recording RAM unit. The data is read out, and similarly to MPEG2, the moving picture compression is performed by the MC unit 120, the Judge unit 110, the DCT unit 130, the Q unit 140, the Rate unit 150, and the VLC unit 160, thereby creating an MPEG4 stream. Also, local decoding similar to MPEG2 is performed, and the decoded image is stored in the recording RAM.

  At this time, information such as the Intra / Inter switching information of the MPEG2 Judgment section, the Q value used for rate control in the Rate section, and the amount of generated code can be referred to in the MPEG4 Rate section. Further, the Inter / Inter switching information can be referred to in the MPEG4 Judge section.

In the MPEG4 section, it is possible to optimize the quantization value and the frame rate as appropriate based on the MPEG2 information. Specifically, the generated code amount and the average quantization value for each MPEG2 input image, the intra / inter coding switching status of each macroblock, and the quantization coefficient are monitored. For images with abrupt changes in these coefficients, processing that makes it easier to increase the quantization value in MPEG4 on the assumption that it is a scene change, processing that makes Intra encoding easier to select in encoding each macroblock, Processing for converting the image itself into Intra encoding, processing for thinning out the image without encoding the image itself, and the like are performed. Also, in the image, each quantization value of MPEG2 and the switching status of Intra / Inter coding are monitored to determine the difficulty level of the coding in the image, and the corresponding quantization value and Intra / Inter code Controls the switching of data. By performing MPEG4 encoding using MPEG2 encoding information, it is possible to suppress deterioration in image quality due to abrupt scene changes and to improve the quality of MPEG4 images.
Next, FIG. 3 shows encoding timings when encoding MPEG2 and MPEG4.

  MPEG2 and MPEG4 perform the above encoding operation and encode the input image. MPEG4 stores the scaled input image in the recording RAM and encodes it with a delay from the MPEG2 image encoding. This makes it easy to use MPEG2 encoded information.

  Next, FIG. 4 shows a video camera apparatus using the present image encoding apparatus. The camera unit 500 converts an analog image into a digital image, and the image encoding unit 520 performs MPEG2 or MPEG4 image encoding. As for the voice, analog voice is input by the microphone unit 510, converted into digital voice, and voice coding is performed by the voice coding unit 530. The MUX unit 540 multiplexes audio and image data, and saves it as an MPEG stream in the recording medium 550. The system control unit 570 controls each unit. The image display unit 560 performs conversion such as an image display format (eg, NTSC). The image transfer unit 580 performs control when transferring data recorded in MPEG4 to a mobile phone or the like. MPEG2 and MPEG4 simultaneous encoding is appropriately performed according to the user's selection. The MPEG2 stream is recorded on a recording medium, and the MPEG4 stream is reproduced on the output monitor and transferred to a mobile phone or the like. By using the video camera apparatus of the present embodiment for a surveillance camera system or the like, data encoded in MPEG2 is recorded on a recording medium, and data encoded in MPEG4 is transferred to a communication terminal or the like, so that a change in a captured image occurs. When there is a case (for example, when a camera device catches a criminal), a high-quality image can be provided. When the change in the captured image is large (when the change in the coding information such as the generated code amount is large), the communication terminal side may be notified to the user by an alarm sound or light.

  Next, FIG. 5 shows a digital signal input / output device using this image encoding device and a system configuration diagram using the same. The description of the blocks already described is omitted. Here, a portion indicated by a dotted line is a digital signal input / output device. Here, the output unit 610 transfers the image information to the communication terminal 710, the recording medium 730, the screen display means 720, or the like. Here, the recording medium 730 and the image display means 720 are provided outside, but may be provided inside the digital signal input / output device. Here, the device to which the input unit 600 is connected is not limited to the camera device 700.

DESCRIPTION OF SYMBOLS 1 ... 1st encoding apparatus 2 ... 2nd encoding apparatus 20 ... Image input part 30 ... MC part 40 ... DCT part 50 ... Q part 60 ... VLC Unit 70 ... Rate unit 80 ... Judge unit 90 ... Recording RAM unit 100 ... Scaler unit 110 ... Judge unit 120 ... MC unit 130 ... DCT unit 140 ... Q unit 150 ... Rate part 160 ... VLC part

Claims (1)

In a video camera device capable of recording captured image information on a recording medium,
First encoding means for encoding captured image information at a first rate or a first resolution;
Second encoding means for de-encoding the captured image information at a second rate lower than the first rate or a second resolution lower than the first resolution;
Recording means for recording image information;
Transfer means for transferring image information to the outside,
When the second encoding unit encodes the image information, the second encoding unit performs encoding using the encoding information of the image information in the first encoding unit corresponding to the image information,
The recording means records the image information encoded by the first encoding means,
The video camera apparatus characterized in that the transfer means transfers the image information encoded by the second encoding means to the outside.

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